1. Field of the Invention
The present invention relates to a castor and, more particularly, to a castor for a chair, hand cart, sick bed and the like.
2. Description of the Related Art
A chair comprises a stand and a plurality of castors mounted on the bottom of the stand. A conventional chair castor comprises an upright fixing bolt mounted on the bottom of the stand of the chair, a castor body rotatably mounted on the fixing bolt, a wheel unit including two rollers each rotatably mounted on the castor body and each having a periphery formed with a plurality of locking grooves, and a brake unit including a pressing member pivotally mounted on the castor body and provided with a braking member that is movable into one of the locking grooves of each of the rollers of the wheel unit to lock each of the rollers of the wheel unit onto the castor body. Thus, when the pressing member of the brake unit is pressed, the braking member is movable into one of the locking grooves of each of the rollers of the wheel unit to lock each of the rollers of the wheel unit onto the castor body so as to lock the castor. However, the castor body is rotatable relative to the fixing bolt when each of the rollers of the wheel unit is locked onto the castor body, so that the wheel unit easily slips due to rotation the castor body relative to the fixing bolt, thereby causing inconvenience to a user.